In a stepping motor used as an electromechanical transducer in an electronic timepiece, it is necessary that the motor be as small as possible, that the rotor be located positively within the yoke at each step, and that the motor be easy to assembly and adjust. Moreover, there should be little or no oscillation of the rotor at the termination of a signal or pulse. Finally, the current consumed per step should be a minimum in order that the battery used for powering the motor and thereby the timepiece should last as long as possible.
Motors used for powering timepiece should last as long as possible.
Motors used for powering timepieces have hitherto consumed substantial amounts of current so that the life of a battery powering the timepiece is relatively short. This has been due to the fact that the rotors, in general, have been cylindrical so that the moment of inertia has been a maximum consistent with the size of the opening in the yoke into which the rotor fits. Furthermore, it is desirable that the rotor position itself very difinitely and positively at each reversal of the magnetic field in the yoke. As part of this location process, oscillation of the rotor should be avoided since such oscillation can interfere with the rotation of the rotor in response to the next reversal of polarity. The present invention is designed to overcome these difficulties.